Linear diffusion under various names is used to describe the flux of different diffusive properties. For example, Fick's law describes diffusion of a number of molecules of one gas species within a mixture of several species (the potential is called the concentration or partial pressure); Ohm's law describes the diffusion of electric charge (the electric flux is called electric current, the electric potential is called the voltage); and Fourier's law describes the diffusion of heat in conductors (the thermal potential is called the temperature). The constant of proportionality between the gradient and the flux is called the conductance, e.g. thermal conductance in Fourier's law and electrical conductance in Ohm's law, or diffusivity in Fick's law.
In particular, the effects of heat and its diffusion are becoming increasingly problematic when manufacturing and using integrated circuits (ICs). The dimensions of ICs manufactured using complementary metal-oxide semiconductor (CMOS) technology continue to shrink, which increases their power density. As ICs shrink, their power density tends to increase for two reasons. First, the ICs generally shrink at a rate that is faster than the rate at which their supply voltages decrease. Second, the frequencies at which ICs are operated tend to increase as they shrink, resulting in increasing power losses related to high frequency switching.
Research and development accordingly continue into techniques to address the problems that heat and its diffusion pose to ICs. More generally, research and development continue into ways to more generally apply theories describing linear diffusion to solve various practical problems.